The family Achiridae includes about seven genera and 35 species. The name Achiridae is derived from ancient Greek. A- means “without” and “cheiros” means hands. A reference to the lack of pelvic fins. These are present in most species but very rudimentary. Their common name is American Soles

This family is closely related to the Soleidae family or the True Soles or Soles for short.


Like all flatfish, Achiridae are born upright. As soon as they have grown a bit they fall over. The beak and eyes then move to the right side. The body is round or oval if you include the fins in it. Only Achiropsis doenreri is a bit more elongated.

The lower lip on the eye side has a fleshy edge with fringes. This distinguishes them from other species. On average, the species do not grow larger than about 15 centimetres. Only Achirus achirus can reach a length of about 30 centimetres.

As mentioned, they have no (visible) or even no pectoral fins at all. The caudal fin is separated from the dorsal and anal fin.


The species in this family are mainly found in the coastal areas of America, both on the west and east sides. Achiropsis, Apionichthys, Pnictes and Soleonasus are only found in freshwater in the rivers of northern South America. Only Apionichthys dumerili inhabits the estuaries of the Amazon, Corantijn, Grajaú, Orinoco and Oiapoque, where the freshwater mixes with the saltwater. Two Catathyridium species inhabit the watersheds of the Paraguay-Paraná and Rio Uruguay. The remaining species inhabit brackish water or saltwater coastal areas.


The genera that are part of this family:

  • Achirus
  • Apionichthys
  • Catathyridium
  • Gymnachirus
  • Hypoclinemus
  • Pnectes
  • Trinectes
Achirus achirus